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 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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package javax.sound.midi;


/**
 * A <code>MidiChannel</code> object represents a single MIDI channel.
 * Generally, each <code>MidiChannel</code> method processes a like-named MIDI
 * "channel voice" or "channel mode" message as defined by the MIDI specification. However,
 * <code>MidiChannel</code> adds some "get" methods  that retrieve the value
 * most recently set by one of the standard MIDI channel messages.  Similarly,
 * methods for per-channel solo and mute have been added.
 * <p>
 * A <code>{@link Synthesizer}</code> object has a collection
 * of <code>MidiChannels</code>, usually one for each of the 16 channels
 * prescribed by the MIDI 1.0 specification.  The <code>Synthesizer</code>
 * generates sound when its <code>MidiChannels</code> receive
 * <code>noteOn</code> messages.
 * <p>
 * See the MIDI 1.0 Specification for more information about the prescribed
 * behavior of the MIDI channel messages, which are not exhaustively
 * documented here.  The specification is titled <code>MIDI Reference:
 * The Complete MIDI 1.0 Detailed Specification</code>, and is published by
 * the MIDI Manufacturer's Association (<a href = http://www.midi.org>
 * http://www.midi.org</a>).
 * <p>
 * MIDI was originally a protocol for reporting the gestures of a keyboard
 * musician.  This genesis is visible in the <code>MidiChannel</code> API, which
 * preserves such MIDI concepts as key number, key velocity, and key pressure.
 * It should be understood that the MIDI data does not necessarily originate
 * with a keyboard player (the source could be a different kind of musician, or
 * software).  Some devices might generate constant values for velocity
 * and pressure, regardless of how the note was performed.
 * Also, the MIDI specification often leaves it up to the
 * synthesizer to use the data in the way the implementor sees fit.  For
 * example, velocity data need not always be mapped to volume and/or brightness.
 *
 * @author David Rivas
 * @author Kara Kytle
 * @see Synthesizer#getChannels
 */

public interface MidiChannel {

  /**
   * Starts the specified note sounding.  The key-down velocity
   * usually controls the note's volume and/or brightness.
   * If <code>velocity</code> is zero, this method instead acts like
   * {@link #noteOff(int)}, terminating the note.
   *
   * @param noteNumber the MIDI note number, from 0 to 127 (60 = Middle C)
   * @param velocity the speed with which the key was depressed
   * @see #noteOff(int, int)
   */
  public void noteOn(int noteNumber, int velocity);

  /**
   * Turns the specified note off.  The key-up velocity, if not ignored, can
   * be used to affect how quickly the note decays.
   * In any case, the note might not die away instantaneously; its decay
   * rate is determined by the internals of the <code>Instrument</code>.
   * If the Hold Pedal (a controller; see
   * {@link #controlChange(int, int) controlChange})
   * is down, the effect of this method is deferred until the pedal is
   * released.
   *
   * @param noteNumber the MIDI note number, from 0 to 127 (60 = Middle C)
   * @param velocity the speed with which the key was released
   * @see #noteOff(int)
   * @see #noteOn
   * @see #allNotesOff
   * @see #allSoundOff
   */
  public void noteOff(int noteNumber, int velocity);

  /**
   * Turns the specified note off.
   *
   * @param noteNumber the MIDI note number, from 0 to 127 (60 = Middle C)
   * @see #noteOff(int, int)
   */
  public void noteOff(int noteNumber);

  /**
   * Reacts to a change in the specified note's key pressure.
   * Polyphonic key pressure
   * allows a keyboard player to press multiple keys simultaneously, each
   * with a different amount of pressure.  The pressure, if not ignored,
   * is typically used to vary such features as the volume, brightness,
   * or vibrato of the note.
   *
   * It is possible that the underlying synthesizer
   * does not support this MIDI message. In order
   * to verify that <code>setPolyPressure</code>
   * was successful, use <code>getPolyPressure</code>.
   *
   * @param noteNumber the MIDI note number, from 0 to 127 (60 = Middle C)
   * @param pressure value for the specified key, from 0 to 127 (127 = maximum pressure)
   * @see #getPolyPressure(int)
   */
  public void setPolyPressure(int noteNumber, int pressure);

  /**
   * Obtains the pressure with which the specified key is being depressed.
   *
   * @param noteNumber the MIDI note number, from 0 to 127 (60 = Middle C)
   *
   * If the device does not support setting poly pressure, this method always returns 0. Calling
   * <code>setPolyPressure</code> will have no effect then.
   * @return the amount of pressure for that note, from 0 to 127 (127 = maximum pressure)
   * @see #setPolyPressure(int, int)
   */
  public int getPolyPressure(int noteNumber);

  /**
   * Reacts to a change in the keyboard pressure.  Channel
   * pressure indicates how hard the keyboard player is depressing
   * the entire keyboard.  This can be the maximum or
   * average of the per-key pressure-sensor values, as set by
   * <code>setPolyPressure</code>.  More commonly, it is a measurement of
   * a single sensor on a device that doesn't implement polyphonic key
   * pressure.  Pressure can be used to control various aspects of the sound,
   * as described under {@link #setPolyPressure(int, int) setPolyPressure}.
   *
   * It is possible that the underlying synthesizer
   * does not support this MIDI message. In order
   * to verify that <code>setChannelPressure</code>
   * was successful, use <code>getChannelPressure</code>.
   *
   * @param pressure the pressure with which the keyboard is being depressed, from 0 to 127 (127 =
   * maximum pressure)
   * @see #setPolyPressure(int, int)
   * @see #getChannelPressure
   */
  public void setChannelPressure(int pressure);

  /**
   * Obtains the channel's keyboard pressure.
   * If the device does not support setting channel pressure,
   * this method always returns 0. Calling
   * <code>setChannelPressure</code> will have no effect then.
   *
   * @return the amount of pressure for that note, from 0 to 127 (127 = maximum pressure)
   * @see #setChannelPressure(int)
   */
  public int getChannelPressure();

  /**
   * Reacts to a change in the specified controller's value.  A controller
   * is some control other than a keyboard key, such as a
   * switch, slider, pedal, wheel, or breath-pressure sensor.
   * The MIDI 1.0 Specification provides standard numbers for typical
   * controllers on MIDI devices, and describes the intended effect
   * for some of the controllers.
   * The way in which an
   * <code>Instrument</code> reacts to a controller change may be
   * specific to the <code>Instrument</code>.
   * <p>
   * The MIDI 1.0 Specification defines both 7-bit controllers
   * and 14-bit controllers.  Continuous controllers, such
   * as wheels and sliders, typically have 14 bits (two MIDI bytes),
   * while discrete controllers, such as switches, typically have 7 bits
   * (one MIDI byte).  Refer to the specification to see the
   * expected resolution for each type of control.
   * <p>
   * Controllers 64 through 95 (0x40 - 0x5F) allow 7-bit precision.
   * The value of a 7-bit controller is set completely by the
   * <code>value</code> argument.  An additional set of controllers
   * provide 14-bit precision by using two controller numbers, one
   * for the most significant 7 bits and another for the least significant
   * 7 bits.  Controller numbers 0 through 31 (0x00 - 0x1F) control the
   * most significant 7 bits of 14-bit controllers; controller numbers
   * 32 through 63 (0x20 - 0x3F) control the least significant 7 bits of
   * these controllers.  For example, controller number 7 (0x07) controls
   * the upper 7 bits of the channel volume controller, and controller
   * number 39 (0x27) controls the lower 7 bits.
   * The value of a 14-bit controller is determined
   * by the interaction of the two halves.  When the most significant 7 bits
   * of a controller are set (using controller numbers 0 through 31), the
   * lower 7 bits are automatically set to 0.  The corresponding controller
   * number for the lower 7 bits may then be used to further modulate the
   * controller value.
   *
   * It is possible that the underlying synthesizer
   * does not support a specific controller message. In order
   * to verify that a call to <code>controlChange</code>
   * was successful, use <code>getController</code>.
   *
   * @param controller the controller number (0 to 127; see the MIDI 1.0 Specification for the
   * interpretation)
   * @param value the value to which the specified controller is changed (0 to 127)
   * @see #getController(int)
   */
  public void controlChange(int controller, int value);

  /**
   * Obtains the current value of the specified controller.  The return
   * value is represented with 7 bits. For 14-bit controllers, the MSB and
   * LSB controller value needs to be obtained separately. For example,
   * the 14-bit value of the volume controller can be calculated by
   * multiplying the value of controller 7 (0x07, channel volume MSB)
   * with 128 and adding the
   * value of controller 39 (0x27, channel volume LSB).
   *
   * If the device does not support setting a specific controller,
   * this method returns 0 for that controller.
   * Calling <code>controlChange</code> will have no effect then.
   *
   * @param controller the number of the controller whose value is desired. The allowed range is
   * 0-127; see the MIDI 1.0 Specification for the interpretation.
   * @return the current value of the specified controller (0 to 127)
   * @see #controlChange(int, int)
   */
  public int getController(int controller);

  /**
   * Changes a program (patch).  This selects a specific
   * instrument from the currently selected bank of instruments.
   * <p>
   * The MIDI specification does not
   * dictate whether notes that are already sounding should switch
   * to the new instrument (timbre) or continue with their original timbre
   * until terminated by a note-off.
   * <p>
   * The program number is zero-based (expressed from 0 to 127).
   * Note that MIDI hardware displays and literature about MIDI
   * typically use the range 1 to 128 instead.
   *
   * It is possible that the underlying synthesizer
   * does not support a specific program. In order
   * to verify that a call to <code>programChange</code>
   * was successful, use <code>getProgram</code>.
   *
   * @param program the program number to switch to (0 to 127)
   * @see #programChange(int, int)
   * @see #getProgram()
   */
  public void programChange(int program);

  /**
   * Changes the program using bank and program (patch) numbers.
   *
   * It is possible that the underlying synthesizer
   * does not support a specific bank, or program. In order
   * to verify that a call to <code>programChange</code>
   * was successful, use <code>getProgram</code> and
   * <code>getController</code>.
   * Since banks are changed by way of control changes,
   * you can verify the current bank with the following
   * statement:
   * <pre>
   *   int bank = (getController(0) * 128)
   *              + getController(32);
   * </pre>
   *
   * @param bank the bank number to switch to (0 to 16383)
   * @param program the program (patch) to use in the specified bank (0 to 127)
   * @see #programChange(int)
   * @see #getProgram()
   */
  public void programChange(int bank, int program);

  /**
   * Obtains the current program number for this channel.
   *
   * @return the program number of the currently selected patch
   * @see Patch#getProgram
   * @see Synthesizer#loadInstrument
   * @see #programChange(int)
   */
  public int getProgram();

  /**
   * Changes the pitch offset for all notes on this channel.
   * This affects all currently sounding notes as well as subsequent ones.
   * (For pitch bend to cease, the value needs to be reset to the
   * center position.)
   * <p> The MIDI specification
   * stipulates that pitch bend be a 14-bit value, where zero
   * is maximum downward bend, 16383 is maximum upward bend, and
   * 8192 is the center (no pitch bend).  The actual
   * amount of pitch change is not specified; it can be changed by
   * a pitch-bend sensitivity setting.  However, the General MIDI
   * specification says that the default range should be two semitones
   * up and down from center.
   *
   * It is possible that the underlying synthesizer
   * does not support this MIDI message. In order
   * to verify that <code>setPitchBend</code>
   * was successful, use <code>getPitchBend</code>.
   *
   * @param bend the amount of pitch change, as a nonnegative 14-bit value (8192 = no bend)
   * @see #getPitchBend
   */
  public void setPitchBend(int bend);

  /**
   * Obtains the upward or downward pitch offset for this channel.
   * If the device does not support setting pitch bend,
   * this method always returns 8192. Calling
   * <code>setPitchBend</code> will have no effect then.
   *
   * @return bend amount, as a nonnegative 14-bit value (8192 = no bend)
   * @see #setPitchBend(int)
   */
  public int getPitchBend();

  /**
   * Resets all the implemented controllers to their default values.
   *
   * @see #controlChange(int, int)
   */
  public void resetAllControllers();

  /**
   * Turns off all notes that are currently sounding on this channel.
   * The notes might not die away instantaneously; their decay
   * rate is determined by the internals of the <code>Instrument</code>.
   * If the Hold Pedal controller (see
   * {@link #controlChange(int, int) controlChange})
   * is down, the effect of this method is deferred until the pedal is
   * released.
   *
   * @see #allSoundOff
   * @see #noteOff(int)
   */
  public void allNotesOff();

  /**
   * Immediately turns off all sounding notes on this channel, ignoring the
   * state of the Hold Pedal and the internal decay rate of the current
   * <code>Instrument</code>.
   *
   * @see #allNotesOff
   */
  public void allSoundOff();

  /**
   * Turns local control on or off.  The default is for local control
   * to be on.  The "on" setting means that if a device is capable
   * of both synthesizing sound and transmitting MIDI messages,
   * it will synthesize sound in response to the note-on and
   * note-off messages that it itself transmits.  It will also respond
   * to messages received from other transmitting devices.
   * The "off" setting means that the synthesizer will ignore its
   * own transmitted MIDI messages, but not those received from other devices.
   *
   * It is possible that the underlying synthesizer
   * does not support local control. In order
   * to verify that a call to <code>localControl</code>
   * was successful, check the return value.
   *
   * @param on <code>true</code> to turn local control on, <code>false</code> to turn local control
   * off
   * @return the new local-control value, or false if local control is not supported
   */
  public boolean localControl(boolean on);

  /**
   * Turns mono mode on or off.  In mono mode, the channel synthesizes
   * only one note at a time.  In poly mode (identical to mono mode off),
   * the channel can synthesize multiple notes simultaneously.
   * The default is mono off (poly mode on).
   * <p>
   * "Mono" is short for the word "monophonic," which in this context
   * is opposed to the word "polyphonic" and refers to a single synthesizer
   * voice per MIDI channel.  It
   * has nothing to do with how many audio channels there might be
   * (as in "monophonic" versus "stereophonic" recordings).
   *
   * It is possible that the underlying synthesizer
   * does not support mono mode. In order
   * to verify that a call to <code>setMono</code>
   * was successful, use <code>getMono</code>.
   *
   * @param on <code>true</code> to turn mono mode on, <code>false</code> to turn it off (which
   * means turning poly mode on).
   * @see #getMono
   * @see VoiceStatus
   */
  public void setMono(boolean on);

  /**
   * Obtains the current mono/poly mode.
   * Synthesizers that do not allow changing mono/poly mode
   * will always return the same value, regardless
   * of calls to <code>setMono</code>.
   *
   * @return <code>true</code> if mono mode is on, otherwise <code>false</code> (meaning poly mode
   * is on).
   * @see #setMono(boolean)
   */
  public boolean getMono();

  /**
   * Turns omni mode on or off.  In omni mode, the channel responds
   * to messages sent on all channels.  When omni is off, the channel
   * responds only to messages sent on its channel number.
   * The default is omni off.
   *
   * It is possible that the underlying synthesizer
   * does not support omni mode. In order
   * to verify that <code>setOmni</code>
   * was successful, use <code>getOmni</code>.
   *
   * @param on <code>true</code> to turn omni mode on, <code>false</code> to turn it off.
   * @see #getOmni
   * @see VoiceStatus
   */
  public void setOmni(boolean on);

  /**
   * Obtains the current omni mode.
   * Synthesizers that do not allow changing the omni mode
   * will always return the same value, regardless
   * of calls to <code>setOmni</code>.
   *
   * @return <code>true</code> if omni mode is on, otherwise <code>false</code> (meaning omni mode
   * is off).
   * @see #setOmni(boolean)
   */
  public boolean getOmni();

  /**
   * Sets the mute state for this channel. A value of
   * <code>true</code> means the channel is to be muted, <code>false</code>
   * means the channel can sound (if other channels are not soloed).
   * <p>
   * Unlike {@link #allSoundOff()}, this method
   * applies to only a specific channel, not to all channels.  Further, it
   * silences not only currently sounding notes, but also subsequently
   * received notes.
   *
   * It is possible that the underlying synthesizer
   * does not support muting channels. In order
   * to verify that a call to <code>setMute</code>
   * was successful, use <code>getMute</code>.
   *
   * @param mute the new mute state
   * @see #getMute
   * @see #setSolo(boolean)
   */
  public void setMute(boolean mute);

  /**
   * Obtains the current mute state for this channel.
   * If the underlying synthesizer does not support
   * muting this channel, this method always returns
   * <code>false</code>.
   *
   * @return <code>true</code> the channel is muted, or <code>false</code> if not
   * @see #setMute(boolean)
   */
  public boolean getMute();

  /**
   * Sets the solo state for this channel.
   * If <code>solo</code> is <code>true</code> only this channel
   * and other soloed channels will sound. If <code>solo</code>
   * is <code>false</code> then only other soloed channels will
   * sound, unless no channels are soloed, in which case all
   * unmuted channels will sound.
   *
   * It is possible that the underlying synthesizer
   * does not support solo channels. In order
   * to verify that a call to <code>setSolo</code>
   * was successful, use <code>getSolo</code>.
   *
   * @param soloState new solo state for the channel
   * @see #getSolo()
   */
  public void setSolo(boolean soloState);

  /**
   * Obtains the current solo state for this channel.
   * If the underlying synthesizer does not support
   * solo on this channel, this method always returns
   * <code>false</code>.
   *
   * @return <code>true</code> the channel is solo, or <code>false</code> if not
   * @see #setSolo(boolean)
   */
  public boolean getSolo();
}
